<?php //$Id: grade_export_xml.php,v 1.22.2.1 2008/02/26 08:00:10 moodler Exp $

///////////////////////////////////////////////////////////////////////////
//																	   //
// NOTICE OF COPYRIGHT												   //
//																	   //
// Moodle - Modular Object-Oriented Dynamic Learning Environment		 //
//		  http://moodle.com											//
//																	   //
// Copyright (C) 1999 onwards  Martin Dougiamas  http://moodle.com	   //
//																	   //
// This program is free software; you can redistribute it and/or modify  //
// it under the terms of the GNU General Public License as published by  //
// the Free Software Foundation; either version 2 of the License, or	 //
// (at your option) any later version.								   //
//																	   //
// This program is distributed in the hope that it will be useful,	   //
// but WITHOUT ANY WARRANTY; without even the implied warranty of		//
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the		 //
// GNU General Public License for more details:						  //
//																	   //
//		  http://www.gnu.org/copyleft/gpl.html						 //
//																	   //
///////////////////////////////////////////////////////////////////////////

require_once($CFG->dirroot.'/grade/export/lib.php');

class grade_export_xml extends grade_export {

	var $plugin = 'xml';
	var $updatedgradesonly = false; // default to export ALL grades
	
	/**
	 * To be implemented by child classes
	 * @param boolean $feedback
	 * @param boolean $publish Whether to output directly, or send as a file
	 * @return string
	 */
	function print_grades($feedback = false) {
		global $CFG;
		require_once($CFG->libdir.'/filelib.php');

		$export_tracking = $this->track_exports();

		$strgrades = get_string('grades');

		/// Calculate file name
		$downloadfilename = clean_filename("{$this->course->shortname} $strgrades.xml");

		make_upload_directory('temp/gradeexport', false);
		$tempfilename = $CFG->dataroot .'/temp/gradeexport/'. md5(sesskey().microtime().$downloadfilename);
		if (!$handle = fopen($tempfilename, 'w+b')) {
			error("Could not create a temporary file into which to dump the XML data.");
			return false;
		}

		/// time stamp to ensure uniqueness of batch export
		fwrite($handle,  '<results batch="xml_export_'.time().'">'."\n");

		$export_buffer = array();

		$geub = new grade_export_update_buffer();
		$gui = new graded_users_iterator($this->course, $this->columns, $this->groupid);
		$gui->init();
		while ($userdata = $gui->next_user()) {
			$user = $userdata->user;

			if (empty($user->idnumber)) {
				//id number must exist
				continue;
			}

			// studentgrades[] index should match with corresponding $index
			foreach ($userdata->grades as $itemid => $grade) {
				$grade_item = $this->grade_items[$itemid];
				$grade->grade_item =& $grade_item;
				$gradestr = $this->format_grade($grade); // no formating for now
				
				// MDL-11669, skip exported grades or bad grades (if setting says so)
				if ($export_tracking) {
					$status = $geub->track($grade);
					if ($this->updatedgradesonly && ($status == 'nochange' || $status == 'unknown')) {
						continue; 
					}
				}

				fwrite($handle,  "\t<result>\n");

				if ($export_tracking) {
					fwrite($handle,  "\t\t<state>$status</state>\n");
				}

				// only need id number
				fwrite($handle,  "\t\t<assignment>{$grade_item->idnumber}</assignment>\n");
				// this column should be customizable to use either student id, idnumber, uesrname or email.
				fwrite($handle,  "\t\t<student>{$user->idnumber}</student>\n");
				fwrite($handle,  "\t\t<score>$gradestr</score>\n");
				if ($this->export_feedback) {
					$feedbackstr = $this->format_feedback($userdata->feedbacks[$itemid]);
					fwrite($handle,  "\t\t<feedback>$feedbackstr</feedback>\n");
				}
				fwrite($handle,  "\t</result>\n");
			}
		}
		fwrite($handle,  "</results>");
		fclose($handle);
		$gui->close();
		$geub->close();

		@header('Cache-Control: private, must-revalidate, pre-check=0, post-check=0, max-age=0');
		@header('Expires: '. gmdate('D, d M Y H:i:s', 0) .' GMT');
		@header('Pragma: no-cache');
		header("Content-type: text/xml; charset=UTF-8");
		header("Content-Disposition: attachment; filename=\"$downloadfilename\"");

		readfile_chunked($tempfilename);

		@unlink($tempfilename);

		exit();
	}
}

?>
